1. Field of the Invention
The present invention relates to electrical connectors to be mounted on a circuit board such that the connector receiving opening is flush with an edge of the circuit board.
2. Description of the Related Art
Japanese patent application Kokai No. 254453/95 discloses an electrical connector of this type. FIG. 2 shows such an electrical connector 50 mounted on a circuit board P. The connector 50 has a housing 51 with a pair of flanges 52 on opposite sides attached to the circuit board P. The front face of the housing 51 is flush with an edge of the circuit board P, and a receiving cavity 53 extends rearwardly from the front face of the housing 51. The receiving cavity 53 receives a plugging section 61 of a mating connector 60 and has a rectangular shape as viewed from front. A plurality of arranging grooves 55 for contact elements 54 are provided at the center of the receiving cavity 53, and a pair of coaxial connectors 56 are provided on opposite sides of the arranging grooves. A key projection 57 is provided so as to project into the receiving cavity 53 and fit into a key groove 62 of the mating connector 60 to prevent plugging errors of the connectors.
When the connector 50 is plugged over the mating connector 60, the contact elements 54 and the coaxial connectors 56 are connected to the corresponding contact elements and coaxial connectors of the mating connector 60.
As electronic equipment becomes compact, there is a demand for compact connectors especially for low-profile connectors. In FIG. 2, the height of a connector from the circuit board is desired to be small, and the height of the receiving cavity 53 must be small.
Under such circumstances, the present of the key projection 57 puts a limit to arrangement of the contact elements. For example, no contact elements are provided on the arranging grooves 55 at an area facing the key projection 57. Thus, the space within the receiving cavity 53 is not fully utilized.
In such a conventional connector, a part of the function in the receiving cavity must be given up, or the height of the connector must be increased by that much.